Abstract
BACKGROUND: Diagnostic stability in child and adolescent psychiatry is a key indicator of validity and essential for clinical decision-making. Few longitudinal studies have examined diagnostic trajectories after a first emergency psychiatric contact. METHODS: We conducted a retrospective observational cohort study at Santa Maria University Hospital (Lleida, Spain). A total of 583 patients aged 4-18 years presenting for their first psychiatric emergency visit between 2017 and 2023 were included, with 24-month follow-up. Sociodemographic and clinical data were extracted from Electronic Health Records. Diagnostic transitions were summarized using transition matrices. An exploratory association analysis (Apriori algorithm) identified frequent T1→T2 patterns, reported with confidence and lift. Diagnostic stability was defined as the proportion of patients retaining the same diagnosis at follow-up. RESULTS: Median age at baseline 14.9 years (interquartile range [13-16]); 54.55% were female. Schizophrenia/psychosis showed the highest stability (71%), followed by intellectual disability with gender identity disorder (67%). Mood disorders showed moderate stability (~44%), while others such as eating disorders (26%) or conduct disorders (17%) had lower stability. The strongest associations were "no prior diagnosis → eating disorder" (confidence = 1.00; lift = 12.76) and "autism spectrum disorder + attention-deficit/hyperactivity disorder (ADHD) → conduct disorders" (confidence = 0.66; lift = 2.55). CONCLUSIONS: Diagnostic stability is heterogeneous, with high persistence in schizophrenia/psychosis and low in eating disorders and ADHD. Association analysis identified specific trajectories that may help anticipate clinical evolution. Findings highlight the importance of longitudinal evaluation in early psychiatric care.